This is a thought that came to me when I was following a caravan – I don’t really know how far I can see. I started to think that perhaps some sort of fog of war could be in order (map would be slightly “shrouded” by clouds/mist/blizzard, etc. Something significant enough to tell you “you can’t see what’s going on here, but not strong enough to make seeing the actual map – terrain, etc. – too hard)? Or perhaps there could be a drawn map (think: Total War, Endless Legend style) that could be then uncovered. The parts you lost contact with could then be covered by fog of war.
I understand it’s a lot of work for not too big an effect (in terms of gameplay), but I thought I will just leave it there just in case. After all strategic map is to be reworked at some point, if I recall correctly, so maybe this idea will be of use.